Ice sinks at ice out????

[cowislander]

Can someone explain just what happens? Ive heard many people claim that the ice sinks just before ice out. Since H20 is one of those rare substances that is less dense in its solid phase (ice) then it is in its liquid phase (water) I dont think its possible for it to sink. Can someone explain??

[ITD]

You're right, ice is less dense than water and will float. The only thing I can think of is that before the ice is broken up, as it is melting, the top surface becomes wet making it appear as though the ice is below the surface of the water, hence people think it is sinking. In reality this water is just trapped above the ice until it starts to break up. If the ice did actually sink, you would never hear of docks being destroyed by wind driven ice flows. Come to think of it, if ice sank, we wouldn't be able to walk, drive, skate on it because it would be at the BOTTOM of the lake. ;)

[Professor and Mary Ann]

It melts just like the ice in your drink except with the help of the sun and wind agitatation (waves). The Sun and warmer temperatures will cause the ice to become very unstable resulting it to become composed of these verticle tube-like structures, the waves will break it apart very easily when it reaches this state and the warmer water and sun will do the rest.

[Rattlesnake Gal]

Check out this site.

http://squamlakes.org/sla/ecology.htm

[cowislander]

Interesting bit on the Squam link. However, it really only explains density differences in the liquid phase. Years ago when I was scuba diving off Cow it was shocking how cold the water was at about 50 feet. Even in a 1/4" wetsuit it was nearly unbearable. I'd say about 40 degrees in July. These thermoclines are significant.

Anyway, I've always thought it was as several of you said, a thin layer of water trapped on top of the remaining ice, giving the appearance of "sinking" ice.

Thanks......

[meredith necker]

I don't think that the ice "goes out" the same way every year. Some years it is light colored when it goes out and some years it is black and rotten. I think as well as temperature, weight from rain and also wind are big factors.

[KevinPlante]

If ice was more dense than water, life wouldn't exist on this planet.

The reason the lake water is so much colder deep down is because the sun heats the water closer to the surface first.

[JDeere]

With 15 to 25 MPH north winds forecast for Thursday I would say the lake should be wide open for some salmon fishing on Friday.

[Brian]

I'm looking at Paugus Bay and can see someone out there fishing now.